HTML 5 has brought in a new generation of web-pages and now we should move ahead and forget some past things which we used to do regularly. I am in no mood to confuse you so I will directly come to the point! HTML 5 has included a lot of new Tags which I am going to tell you soon, but first we need to stop the usage of some Old HTML Tags which no longer function in HTML 5.
The <acronym> tag was used to define acronyms in HTML 4. An acronym can be spoken as if it were a word, example NATO, NASA, ASAP, GUI.
The <applet> tag was used to define an embedded applet. You can use the<object> Tag instead of it now!
The <basefont> tag was used to define a default font-color, font-size, or font-family for all the text in a document. But we can use CSS for this purpose now!
The <big> tag was used to make text bigger.
The <center> tag was used to center align text and content. We can use CSS for this purpose now.
The <dir> tag was used to define a directory list. But we can still use the <ol> and <ul> Tags.
The <font> tag was used to define font face, font size, and font color of text. It was among the most used tags in HTML 4 but we have to use CSS for this purpose now.
The <frame> tag was used to define one particular window (frame) within a frameset.
The <frameset> tag was used to define a frameset, which organized multiple windows (frames).
Note: The Frame and Frameset tags are removed because it hinders the usability of the web-page. Also, it has negative SEO implications.
The <noframes> tag was used to display text for browsers that do not handle frames. When frames are not supported then there is no need for noframes.
<s> Tag and <strike> Tag
The <s> and <strike> tags were used to define strike-through the text. We can still use <del> instead. Also, it can be handled using CSS.
The <tt> tag was used to define teletype text. But now we can use CSS for this purpose.
The <u> tag was used to define underlined text. But now we need to use CSS.
The <xmp> tag was used to define pre-formatted text. But we can still use the <pre> tag for this purpose.
Do let me know, if you know any more tags that do not function with HTML5. You can always try the Online HTML Editor !